It's understandable why, at first glance, Meadowmat might appear to be a good green roofing material...especially for anyone who is aiming for biodiversity on the roof. At Q Lawns, we also grow Enviromat sedum matting on our farm and have a green roof maintenance service so we’ve had a little bit of experience with living roofs and in all honesty, Meadowmat isn’t ideal for several reasons
- Meadowmat contains 34 species of native plants, all of which are found naturally in meadows, pastures etc. Some of these plants are adapted to living in really poor soils so they’ve evolved vigorous root systems that can spread a long way to find the nutrients the plants need. Vigorous root systems + green roofs could cause difficulties
- The minimum depth of growing medium to establish Meadowmat into is 150mm. That will weigh around 250Kg per square metre….an awful heavy load to put on a roof unless the building has been designed and built especially to carry that weight
- 50% by weight of the Meadowmat seed mix is grass. A certain amount of native grasses are needed to supply food for insect larvae and shelter for amphibians and small furry creatures. On a roof though, too much grass is a nuisance. Meadows need careful maintenance to ensure that the grasses don’t predominate and crowd out less competitive flowering species. That means taking a cut of hay in the summer….all of which needs to be brought down from the roof, and then mowing it a couple of times during the autumn and winter and again, removing all of the cuttings. Unless you have really good access to the roof, the maintenance regime for Meadowmat just isn’t practical
- Some of the plant species in Meadowmat can grow quite tall (I have Meadowmat in my garden which is currently at hip height) and in windy, blustery conditions, they blow over and all lay on the ground in a heap with the plants on the bottom of the heap being smothered out and killed. On the roof, conditions tend to be more extreme than at ground level…hotter and drier in summer, colder in winter and windier all year round. It’s best to stick to low growing plants that can cope better with the conditions
Enviromat is the ideal vegetation blanket for creating a green roof……..it’s a relatively lightweight build-up and the plants, when in the wild, tend to be found on mountain tops, moors and heaths where they are adapted to living in exposed conditions. There is more information at www.enviromat.co.uk and of course you can email my colleague, Angela Lambert, with any questions you have (Angela is part time, so she might not answer immediately but she will get back to you ASAP)
If you are dead-set on growing wildflowers on your roof, be careful to select ones that are not too tall, can survive in exposed conditions, won’t need a huge amount of maintenance and give a nice long flowering period to provide nectar for butterflies and bees. Also, avoid grass in the seedmix if you can….you’ll find that by sowing wildflower seed or planting wildflower plugs, grass will naturally establish itself in the spaces between flowering plants.